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ConStRuCtIVISt FoundatIons vol. 9, n1

David Vernon is a Professor of Informatics at

the University of Skvde, Sweden. He works on

cognitive systems and is particularly interested

in modeling autonomy. Over the past 34 years, he

has held positions at Westinghouse Electric, Trinity

College Dublin, the European Commission, the

National University of Ireland, Maynooth, Science

Foundation Ireland, and Khalifa University, UAE.

Tool-use Leads to Bodily

Extension, but not Bodily

Incorporation: The Limits

of Mind-as-it-could-be?

Tom FroeseUniversidad Nacional Autnoma de Mxico t.froese/at/gmail.com> Upshot Sato and colleagues make use of an innovative method that com-bines robotics modeling and psycho-logical experimentation to investigate how tool use afects our living and lived embodiment. I situate their approach in a general shift from robotics to human-computer interface studies in enactive cognitive science, and speculate about the necessary conditions for the bodily incorporation of tools.

Putting subjectivity back into the sensorimotor loop 1 Enactive cognitive science (ECS)

is founded on the theory that life and mind

are integrated within a process of sense-

making (hompson 2007). Following its

irst extensive presentation by Francisco

Varela, Evan hompson and Eleanor Rosch

(1991), the paradigm of enaction was oten

loosely grouped with embodied, sensori-

motor, and dynamical approaches to cog-

nition, while its explicit phenomenological

commitments were mostly ignored. and

whereas these latter approaches rapidly led

to the development of new styles of doing

cognitive science and robotics (Wheeler

2005; Clark 2008; Kelso 1995), speciically

enactive research continues to face unique

challenges today. For if we accept that cog-

nition is a form of sense-making, and that

sense-making is the generation and appre-

ciation of meaning from a point of view,

then ECS in contrast to most science and

engineering methods has to place living

and lived subjectivity at the center of all its

endeavors (Froese 2011). 2 here are therefore some unique

methodological challenges for ECS. While

embodied and dynamical approaches can

be satisied with aI and robotics to do a

lot of their theoretical work (e.g., Pfeifer

& Scheier 1999; Beer 2000), enactive aI

is speciically confronted by the profound

problem of how to design a sense-maker

something for which we still lack theo-

retical and practical knowledge (Froese &

Ziemke 2009). Given this impasse, it was to

be expected that ECS would shit its meth-

odological focus from constructing and

analyzing artiicial agents to phenomeno-

logical investigations of human experience

(Froese 2007). However, there is still plenty

of room for innovative use of technology. 3 one of the most resourceful de-

velopments in this direction is a hybrid

methodology that retains the idea of con-

structing new technical systems, but for the

purpose of investigating how tool use via

its efects on our living embodiment mod-

ulates our lived experience (Froese, Suzuki,

ogai & Ikegami 2012). In analogy with arti-

icial lifes objective to use technology to ex-

plore life-as-it-could-be, we can refer to this

ield as artiicial embodiment and deine

its aim as mapping out the space of mind-

as-it-could-be. 4 he authors of the present tar-

get article, Yuki Sato, Hiroyuki Iizuka, and

takashi Ikegami, make a valuable contri-

bution to this cross-disciplinary method

by investigating the phenomenon of ex-

tended embodiment currently a hot topic

(hompson & Stapleton 2009) by bringing

together insights from both robotics mod-

eling and psychological experimentation.

hey thereby join a new generation of enac-

tive researchers who are just as interested in

the dynamics of artiicial agents as they are

in the sense-making of humans, oten relat-

ing these two areas in a mutually inform-

ing manner by making use of custom-built

human-computer interfaces (e.g., Rohde

2010; Iizuka, ando & Maeda 2009; Suzuki,

Wakisaka & Fujii 2012; Suzuki, Garinkel,

Critchley & Seth, in press). In the following,

I situate the work by Sato et al. in this wider

context. I begin by clarifying their method,

and conclude by deriving a new working

hypothesis from their results.

Tool use as a method to investigate mind-as-it-could-be 5 While conducting a study of the

experiential efects of using a sensorimo-

tor substitution device (Froese, McGann,

Bigge, Spiers & Seth 2012), I started work-

ing out a basic methodological scheme for

an enactive approach to consciousness re-

search based on human-computer interfac-

es (HCI). his scheme is nicely illustrated

by the series of psychological experiments

by Sato and colleagues (Figure1). 6 We can see this scheme at work in

the study by Sato et al. as follows. First, they

completed the methodological cycle in the

domain of artiicial life. hey synthesized

an evolutionary robotics model, analyzed

its emergent dynamics, and formulated a

hypothesis, i.e., that tool-based extension

of bodily sensitivity is correlated with the

regularity of the users movements (26). to

test this hypothesis of lived bodily extension

properly, they then conducted a psychologi-

cal experiment on users experience. hey

synthesized a simpliied real version of the single windmill tool to be used with

a stick,

allowed the participants to become skilled users,

analyzed the resulting user experience albeit measured indirectly via objective

success, and

received a partial conirmation of their hypothesis. 7 hey then embarked on the meth-

odological cycle again. hey

constructed a more accurate version of the double-windmill tool,

allowed participants to become sui-ciently skilled,

assessed their experience, and formulated a novel hypothesis.

More speciically, in contrast to their ini-

tial assumption, they found that objective

success at the task is not an appropriate in-

direct measure of the lived experience of bod-

ily extension. Rather, strong and continuous

coupling between user and tool seems to be

more important to shiting their attention

away from the tool (37). his hypothesis

87

The Limits of Mind-as-it-could-be? Tom Froese

Enactive Cognitive Science

http://www.univie.ac.at/constructivism/journal/9/1/073.sato

could not have been derived solely from

the modeling study or just in terms of par-

ticipants objective performance, thereby

conirming the necessity of including irst-

person phenomenological analysis in the

enactive approach and in the science of con-

sciousness more generally.1

From bodily extension to bodily incorporation 8 Based on their new hypothesis,

i.e., that the strength of coupling is expected

to correlate with the strength of feeling bod-

ily extension, Sato et al. propose to conduct

future experiments in which the strength of

coupling between user and tool is the pa-

rameter to be manipulated (46). While it

would be useful to conirm this expectation,

I propose a more radical research agenda.

9 When discussing how people ex-

perience hand-held tools we must take care

to distinguish several possibilities. as Sato

et al. acknowledge (5), the user could be

either focused on the tool as such, in which

case they feel the tool in contact with their

body, or they could be focused on the task,

such that they perceive via the tool and

tactile sensitivity is extended to where the

tool makes contact with the objects being

manipulated. Indeed, it is probably the po-

tential for extended action, rather than con-

stant physical contact per se, that constitutes

the feeling of bodily extension (McGann,

Froese, Bigge, Spiers & Seth 2011). 10 nevertheless, it is also evident

that these tools are not experienced as a

part of the living body, in the way that a

hand is (and a prosthesis should be) felt. We

therefore need to distinguish, following the

proposal by Helena de Preester and Manos

tsakiris (2009), between bodily extension

and bodily incorporation. hey theorize

that a pre-existing body model normatively

constrains which kind of tools can become

incorporated into the living body, namely

those tools that it within the normal human

body plan, such as successful prostheses.

However, the results by Sato et al. hint at an-

1 | a similar dissociation between objective

performance and phenomenological report was

found in a study of alterations in felt embodiment

based on the rubber hand illusion (Rohde, di

Luca & Ernst 2011), showing that the inding by

Sato et al. is not an isolated case.

other possibility, which is more in line with

enactive thinking.

11 he key results found by Sato et

al. are twofold: (a) that the acquisition of

skillful tool use is correlated with increases

in coordinated movements, and (b) that the

feeling of bodily extension via the tool ad-

ditionally depends on strong continuous

physical contact. his dependence on both

physical and coordinated coupling makes

sense, because the living body is a physically

bounded whole of semi-autonomous parts

(Varela 1991) that are linked by coordination

dynamics (Kelso 1995). So why did the sub-

jects not experience bodily incorporation? Is

it because the tools did not it into the hu-

man body model? I am not convinced by

this response. to be sure, Sato et al.s sticks

and windmills do not have direct counter-

parts in our normal body morphology, but

even the designers of the most advanced

prostheses still face signiicant challenges

(Kwok 2013). 12 I suggest that the answer has more

to do with how the movements of the tool

it with the intended actions of the subject.

While the tip of a hand-held stick is ro-

bustly coordinated with the movements of

my hand (the two always move rigidly to-

gether), my hand is adaptively coordinated

with the actions of my arm and body (my

ingers autonomously and correctly adjust

their coniguration depending on whether I

am reaching for my keys or my cofee cup).

hese micro-actions are neither a purely

mechanical process nor are they something

that I intentionally do; they are context-sen-

sitive behaviors situated in between these

extremes (Beaton 2013: 302f). I therefore

suggest that if a tool is to become fully incor-

porated, its movements have to follow their

own localized norms, and these norms must

be in adaptive coordination with the norma-

tive situation of the agent as a whole (Froese,

in press). a step in the right direction might

be to design anticipatory human-computer

interfaces for which the tool-user relation

resembles the coordination dynamics of a

social interaction (Iizuka, ando & Maeda

2009).

Tom Froese completed his D.Phil. in cognitive

science from the University of Sussex in 2009. He is

currently a postdoctoral researcher at the National

Autonomous University of Mexico. He investigates

the relationship between life, mind and sociality

using a variety of methods, including evolutionary

robotics, systems theory, and phenomenology.

Received: 16 october 2013

accepted: 18 october 2013

Emergence

of experience

Collection of data

about characteristics

of user experience

Design of

new human-computer

interface (HCI)

Interpretation of data

according to theory

of lived experience

Acquisition of

practical expertise

in using the HCI

Artificial

Embodiment2

Synthesis

of interface1

Analysis

of experience3

Generation

of hypotheses4

Figure 1: Methodological scheme proposed for a growing ield that, in analogy with the ield of artiicial life, we might call artiicial embodiment. In order to investigate a hypothesis about the embodied mind, a novel human-computer interface (HCI) is constructed with the speciic aim of modulating a users sensorimotor embodiment so as to enable the experimental manipulation of the users irst-person perspective. (Figure adapted from Froese, Suzuki, Ogai & Ikegami 2012).